'\R': Command Not Found [Duplicate]

echo "Select your option:"
echo "1. Change ip address"
echo "2. Add route"
echo "3. Reboot"
echo "4. Exit"
read A
case $A in
    1)
            echo "Add Ip address"
            read IP
            echo "Add Netmask"
            read Netid
            echo "Add name of interface"
            read Interface
            ifconfig ${Interface} ${IP}/${Netid}
            if [ $? -ne 0 ];then
                    echo "Ip address not configured"
            fi
            ;;
    2)
            echo "Add Destination"
            read dst
            echo "Add Netmask"
            read Netid
            echo "Add Gateway"
            read gw
            route add $dst mask $Netid gw $gw
            if [ $? -ne 0 ];then
                    echo "Route not added"
            fi
            ;;
    3)
            reboot
            ;;
    4)
            echo "Bye"
            exit 0
            ;;
    default)
            echo "Wrong selection"
            exit 1
esac

Error:

[b104@b104 Downloads]$ ./NetworkUtility.sh 
./NetworkUtility.sh: line 1: $'\r': command not found
Select your option:
1. Change ip address
2. Add route
3. Reboot
4. Exit
1
': not a valid identifier 7: read: `A
./NetworkUtility.sh: line 8: $'\r': command not found
./NetworkUtility.sh: line 9: syntax error near unexpected token `newline'
'/NetworkUtility.sh: line 9: `case $A in 
[b104@b104 Downloads]$